In the earth-working field, the slope of the land is normally set forth in terms of a ratio of the horizontal distance compared to the vertical distance of the slope. Engineers for landscaping, road building, dam building and the like, indicate to the operator of the grading vehicle the particular finished grade in terms of this slope ratio.
Heretofore, in order to obtain a precise slope ratio, the contractor has had to employ on the site engineers to lay out the grade with a surveyor's level. Indicating markers would have to be placed along the ground indicating the amount of cut and fill necessary at particular points to obtain the finished grade. Most of the time, one or more checks of the grade with the surveyor's level is required in order to obtain the precise slope that is required in such precision engineering projects as road building and dam building. This is a time-consuming and expensive proposition for the grading contractor.
Because of the expense, many contractors are known to instruct their operators to simply "eyeball" the desired slope. A skilled operator can come close to the slope desired, but cannot on a regular basis come within the accuracy that is imposed on most construction projects. When the inaccuracy is noted, the contractor must spend extra time to correct the error in judgment, adding to the cost of the project. It is also known that the "eyeball" method is in itself time-consuming, since the vehicle operator must take extra time in his attempt to properly orient the grade to a true horizontal and/or vertical object or surface.
In any case, I have determined that it would be desirable to have a simple and rugged instrument carried directly on the grading vehicle in order to indicate to the operator with a high degree of accuracy the slope that is being cut.